fix #610 again, correctly this time maybe

Author: bhaller

VERSIONS

@@ -39,7 +39,7 @@ development head (in the master branch):
 	fix #602, (float)rdirichlet(integer$ n, numeric alpha) function to Eidos for Dirichlet distribution draws
 	fix #610, distribution draws behave inconsistently with out-of-range parameters
 		rlnorm() accepted SD < 0 and returned a value; it should error, as rnorm() does (R returns NAN in the SD < 0 case, but erroring is more consistent with Eidos policies)
-		rexp() returned zero for a rate of 0, and returned non-zero values for rate < 0; R returns NAN; I decided that these cases should also error, consistent with Eidos policies
+		rexp() returned values for rate < 0; this should also error, consistent with Eidos policies
 
 
 version 5.1 (Eidos version 4.1):

eidos/eidos_functions_distributions.cpp

@@ -1230,8 +1230,8 @@ EidosValue_SP Eidos_ExecuteFunction_rexp(const std::vector<EidosValue_SP> &p_arg
 	{
 		double mu0 = arg_mu->NumericAtIndex_NOCAST(0, nullptr);
 
-		if (mu0 <= 0.0)
-			EIDOS_TERMINATION << "ERROR (Eidos_ExecuteFunction_rexp): function rexp() requires mu > 0.0 (" << EidosStringForFloat(mu0) << " supplied)." << EidosTerminate(nullptr);
+		if (mu0 < 0.0)
+			EIDOS_TERMINATION << "ERROR (Eidos_ExecuteFunction_rexp): function rexp() requires mu >= 0.0 (" << EidosStringForFloat(mu0) << " supplied)." << EidosTerminate(nullptr);
 
 		EidosValue_Float *float_result = (new (gEidosValuePool->AllocateChunk()) EidosValue_Float())->resize_no_initialize(num_draws);
 		result_SP = EidosValue_SP(float_result);
@@ -1262,7 +1262,7 @@ EidosValue_SP Eidos_ExecuteFunction_rexp(const std::vector<EidosValue_SP> &p_arg
 			{
 				double mu = arg_mu->NumericAtIndex_NOCAST((int)draw_index, nullptr);
 
-				if (mu <= 0.0)
+				if (mu < 0.0)
 				{
 					saw_error = true;
 					continue;
@@ -1273,7 +1273,7 @@ EidosValue_SP Eidos_ExecuteFunction_rexp(const std::vector<EidosValue_SP> &p_arg
 		}
 
 		if (saw_error)
-			EIDOS_TERMINATION << "ERROR (Eidos_ExecuteFunction_rexp): function rexp() requires mu > 0.0." << EidosTerminate(nullptr);
+			EIDOS_TERMINATION << "ERROR (Eidos_ExecuteFunction_rexp): function rexp() requires mu >= 0.0." << EidosTerminate(nullptr);
 	}
 
 	return result_SP;

eidos/eidos_test_functions_statistics.cpp

@@ -852,10 +852,10 @@ void _RunFunctionDistributionTests(void)
 	EidosAssertScriptSuccess_LV("setSeed(2); abs(rexp(3, 100000) - c(28842.1, 31355.3, 102831.0)) < 0.1;", {true, true, true});
 	EidosAssertScriptSuccess_LV("setSeed(3); abs(rexp(3, c(10, 100, 1000)) - c(3.65665, 1.5667, 948.946)) < 0.1;", {true, true, true});
 	EidosAssertScriptRaise("rexp(-1);", 0, "requires n to be");
-	EidosAssertScriptRaise("rexp(2, -0.001);", 0, "requires mu > 0.0");
-	EidosAssertScriptRaise("rexp(2, 0);", 0, "requires mu > 0.0");
-	EidosAssertScriptRaise("rexp(2, c(1.0, -0.001));", 0, "requires mu > 0.0");
-	EidosAssertScriptRaise("rexp(2, c(1.0, 0));", 0, "requires mu > 0.0");
+	EidosAssertScriptSuccess_F("rexp(1, 0);", 0.0);
+	EidosAssertScriptSuccess_FV("rexp(2, 0);", {0.0, 0.0});
+	EidosAssertScriptRaise("rexp(2, -0.001);", 0, "requires mu >= 0.0");
+	EidosAssertScriptRaise("rexp(2, c(1.0, -0.001));", 0, "requires mu >= 0.0");
 	EidosAssertScriptRaise("rexp(3, c(10, 5));", 0, "requires mu to be");
 	EidosAssertScriptSuccess("rexp(1, NAN);", gStaticEidosValue_FloatNAN);